Feed-finger for saw-sharpening machines.



J. P. HEDSTROM.

FEED FINGER FOR SAW SHARPENING MACHINES.

' APPLICATION FILED FEB. 29, 1908.

984,669.- Patented Feb.21, 1911.

JOHN P. HEDSTROM, 0F BIG RAPIDS, MICHIGAN, ASSIGNOB T0 I-IANCI-IETTSWAGE WORKS, OF BIG RAPIDS, MICHIGAN, A CORPORATION OF MICHIGAN.

FEED-FINGER FOR SAW-SHARPENING MACHINES.

To all whom it may concern:

Be it known that I, JOHN P. HnDsTRoM, a citizen of the United States,residing at Big Rapids, in the county of Mecosta and State of Michigan,have invented certain new and useful Improvements in F eed- Fingers forSaw-Sharpening Machines; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to feed fingers for saw sharpening machines.

As is well-known in the art, saw filers have different preferences, somepreferring to have the feed finger engage the saw tooth' nearer thepoint than others.

One object of my invention is toprovide means for quickly and easilyregulating the height at which the feed finger shall engage the sawteeth.

Heretofore feed fingers have been formed of angular or L-shapedmembersbolted to the body-portion of the finger. The contact of thefinger with the saw teeth soon wears away the finger and therebyprevents the finger from feeding the saw the required distance eachtime, besides rendering it imperative to substitute a new finger for theold one in a comparatively short time, entailing some expense.

Another object of my invention, there- 'fore, is to provide a fingerwhich will not quickly wear out, as well as one, the position of whichcan be shifted so that as soon as the wear has effected a considerablewaste of material at one point the position of the finger can be easily,and quickly changed to bring a new surface into engagement with theteeth of the saw. Furthermore, I have so altered the construction thatthe latorally-projecting portion alone of the finger can be replaced ata minimum expense without necessitating the loss of the entire finger,as was heretofore necessary. Also my improved finger can be attached tothe machines now in use in place of the usual L-shaped finger referredto. The wearing Specification of Letters Patent.

Application filed February 29, 1908.

Patented Feb. 21, 1911. Serial No. 418,608.

away of the finger is occasioned not only by 1ts engagement with thesaw, but also by reason of the practically constant attrition of theemery from the sharpening saw.

My improved finger will permit of an ad ustment up or down to suit anystyle of tooth or the preference of the operator.

To these and other ends, my invention consists in certain novel featuresand combinations of parts, such as will be more fully set forthhereinafter and particularly pointed out in the claims.

In the accompanying drawings, Figure -1 is a perspective view of aportion of a sharpening machine equipped with my in vention; Fig. 2 is abottom perspective view of the device removed from the machine; Fig. 3is a view in cross-section, the feed finger being removed; and Fig. 4 isa perspective view.

As generally constructed, the customary machine employed for sharpeningsaws is provided with a table (1) having preferably a raised rib (2)formed at one edge thereof. A vertically-sliding sash or gate, notshown, carries a driven shaft, at one end of which is mounted a grindingwheel of emery, not shown, located above and extending substantiallytransversely of the rib (2). Located in approximate alinement with therib is a vertically extending feed bar (4:) oscillated in any suitablemanner (not shown). Pivotally secured at one end to the feed bar abovethe table is an arm of any approved pattern, but generally angular, asshown. This arm extends toward the rib (2), and to the free end of sucharm is fastened the feed finger. The saw is held between the face of thetable adjacent the rib by any suitable means, not shown. The mechanismof the machineis so timed that when the sash is slid upward to move thegrinding wheel away from the saw, the feed bar is moved forwardly tocause the feed finger to engage one of the teeth of the saw to move thesaw forward one step, the throw of the feed bar being regulated in anyconvenient manner. The feed finger is then drawn backward by the feedbar, the

finger riding over the teeth owing to the pivotal connection of the arm(5) with the bar, and while the finger is moving rearwardly the sash ismoved downwardly automatically to bring the grinding wheel intoengagement with the succeeding tooth of the saw.

In former machines, no provision was made for causing the finger toengage any particular portion of the teeth of the saw and furthermore,as has been stated, the finger is subjected to considerable wearbothbecause of its constant contact with the hardened teeth of the saw andalso because of the constant presence of particles of emery from thegrinding wheel, all of which made it necessary to replace the fingers atfrequent intervals. The former feed finger was of a general L-shapebolted at its rear end to the free end of the arm, with its angleresting upon the rib (2) so that the laterally projecting portion of thefinger would extend across and engage the teeth of the saw. Theyadmitted of no adjustment either vertically or laterally so that thewear takes place at one point only and requires a constant adjustment ofthe throw of the feed bar in order to take up the wear of the finger sothat the saw will be moved forward a predetermined distance each time.As soon as the finger becomes much worn it must be entirely discardedand a new one substituted therefor.

In my invention, I provide a feed finger comprising a plate (7) providedwith apertures (8) (8) to permit it to be fastened to the free end ofthe feed arm (5) in the same manner as were the former feed fingers. Tothe bottom of this plate near its rear edge I preferably secure one endof a supporting strip (9), which may be resilient. This strip extendsforwardly beneath the plate and in the present instance is bowedslightly, the free end of the strip being provided with a hardened steelshoe (10) on its under face, which shoe is adapted to ride upon the rib(2) or if no rib is employed, then upon the table. The plate preferably,though not necessarily, maintains a horizontal position owing to theshape of the angular arm (5) and at its free end is provided with atransverse groove (11), the outer wall of which at one end is cut awayas at (12) for clearance purposes. Received within this groove is arectangular finger (13) of self-hardning steel whose properties are wellknown, such steel being tough and hard and wear-resisting to a degree.This finger projects laterally from the plate (7) and is adapted toengage and feed the saw. The finger is of greater width than the depthof the groove and hence projects above the surface of the plate (7), fora purpose presently to be described. It is obvious that I may make thefinger of either round or rectangular bar steel, and form the groove ofa contour to receive the finger.

In order to retain the finger firmly in position in its seat (11), Ipreferably provide a clamping plate (14:) mounted on the base plate orholder (7) near its free end, the forward edge of the clamping platebeing recessed, as at (15), to overhang and engage the feed finger (13),the clamping plate preferably extending the entire width of the holder,and as one means for causing the clamping plate to tightly engage thefinger,

I provide a screw stud (16) passing through the clamping plate andthrough the holder, a lock nut (17) on the stud adapted to be screweddown tightly against the clamping plate, thereby retaining the feedfinger in its groove (11). It is obvious that by loosening the lock nutthe clamping plate may be loosened to admit of adjusting the feed fingereither in or out laterally, over and over or end for end to bring newsurfaces thereof into contact with the saw. In

fact, there is an almost unlimited number of positions to which thefinger can be adjusted before it need be replaced with another. It canbe moved in or out until one face is worn, then turned over to present anew face which can be adjusted in or out and finally the finger can bereversed end for end and the entire gamut of positions run throughagain. The screw stud (16) also performs another function in addition tothat of coiiperating with the nut to retain the clamping plate inposition. The stud passes through the holder (7) and its lower endengages the support (9). By screwing the stud in or out the finger andits holder are raised or lowered so as to bring the former against thetooth at the desired point.

It is evident that changes might be made in the form and arrangement ofthe several parts described without departing from the spirit and scopeof my invention, and hence I do not wish to limit myself to the exactconstruction herein set forth.

Having thus fully disclosed my invention, what I claim as new is 1. In asaw sharpening machine, the combination with a feed arm, of a holdersecured thereto and having a seat formed therein, a feed finger receivedin the seat, a clamping plate mounted on the holder and engaging thefeed finger, a threaded stud passing through the clamping plate and theholder, the lower end of the stud projecting below the holder, and alocknut on the stud adapted to take against the clamping plate.

2. In a saw sharpening machine the combination with a feed arm, of aholder secured thereto and having a seat formed therein, a feed fingerreceived in the seat, a clamping plate mounted on the holder andengaging the feed finger, a threaded stud ber to regulate the distancebetween the passing through the clamping plate and the member and theholder. 10 holder, the lower end of the stud pro- In test1mony whereof,I aflix my signajeoting below the holder, a lock nut on the ture inpresence of tWo wltnesses.

stud adapted to take against the clamping JOHN P. HEDSTRQM. plate, and asupporting member carried by Witnesses:

and extending beneath the holder, the end RAY L. SWIFT,

of the stud engaging the supporting meln- LOUIS B. HANCHETT.

